This is a listing of various new community, new village, autonomous communities, and other sustainable/regenerative settlements:
This movement is alive and well. https://chartercitiesinstitute.org/our-story/#People. Studying their governance is worthwhile - 
Special Economic and Autonomous Zones
These can be set up with agreement from nations within which the microstate resides. The microstate may thus be semi-autonomous, and may derive security/police services from its respective state or by private contract.
- NewVistas by the Mormons -  -
Special Economic Zones
- Bill Gates Smart Cities -